After time spent working in Denmark, Doughty returned to the UK, where he became an advisor to Labour MP Douglas Alexander.[10] He then worked in various roles for Oxfam International, before becoming the head of Oxfam Cymru in 2011.[11]

In March 2010, prior to the May 2010 General Election, the BBC's political correspondent David Cornock reported [12] that Doughty was one of the candidates on Labour's shortlist for the Pontypridd parliamentary constituency. The other candidates on the short-list were Jayne Brencher, Delyth Evans, Bethan Roberts, and Owen Smith—who was selected and who subsequently retained the seat for Labour at the general election.

Doughty and his father had been long-time family friends of Cardiff South and Penarth Labour MP Alun Michael. Michael said "Stephen Doughty’s father and I first met 40 years ago when I was a youth worker and he was involved with an Army youth group. I have known Stephen since he was a baby".[13] When Alun Michael announced his decision to step down as Cardiff South and Penarth MP in order to stand for election as South Wales Police and Crime Commissioner, the Western Mail reported on 13 July 2012 that Michael had been "interfering inappropriately" in Labour's selection process for his putative successor in the constituency in order to ensure his preferred candidate (Stephen Doughty) was included on the shortlist. Michael subsequently admitted that he had indeed spoken personally to Labour leader Ed Miliband, to the party’s general secretary Iain McNicol and to members of the National Executive Committee, with the purpose of "preventing a stitch-up" and "stopping a candidate from outside being imposed on the local party".[13] After Michael's intervention Doughty's name was included in the final short list along with four other candidates, Kate Groucutt, Karen Wilkie, Nick Thomas-Symonds and Jeremy Miles. Doughty was selected in a vote by constituency Labour Party members on 14 July 2012.[14]

In the parliamentary by-election on 15 November 2012, Doughty was voted in as the Labour MP for Cardiff South and Penarth. He took the seat with a majority of 5,334, taking 47.3% of the vote.[4] This enhanced Labour's majority in the area, which previously stood at 4,709.[15]

In the reshuffle following the 2015 General Election, Doughty joined the Business, Innovation and Skills team as Shadow Minister for Trade and Industry.[18]

In October 2015, he was moved to a position as a Shadow Foreign Office Minister with responsibility for Africa, South Asia and International Organisations, under Shadow Foreign SecretaryHilary Benn.[5]

In December 2015 Stephen Doughty made the decision to support air strikes against Syria, a decision for which he was criticized by many of his constituents and political activists via social media. Mr Doughty called the police to deal with the 'personal threats' he had received.[19]

In January 2016, Doughty announced that he had resigned as a shadow Foreign Minister on the live Daily Politics programme, saying that he supported the sacked Pat McFadden's views on terrorism and accusing members of the Labour leadership team of lying about the reasons for McFadden's sacking.[20] According to McFadden he was sacked for comments in the debate on the Paris bombings which condemned "the view that sees terrorist acts as always being a response or a reaction to what we in the west do".[21]

Doughty's appearance on the Daily Politics became contentious after it emerged that Laura Kuenssberg, the BBC’s political editor, had arranged for Doughty to make his public announcement on the programme just before Prime Minister's Questions. According to Labour's spokesman, it was an "unacceptable breach of the BBC's role and statutory obligations. By the BBC's own account, BBC journalists and presenters proposed and secured the resignation of a shadow minister on air ... apparently to ensure maximum news and political impact."[22] The Labour Party's Director of Communications Seumas Milne made a formal complaint to the BBC.[23] "Neither the programme production team, nor Laura, played any part in his decision to resign", Robbie Gibb, the BBC head of live political programmes wrote to Milne. "As you know it is a long standing tradition that political programmes on the BBC, along with all other news outlets, seek to break stories. It is true that we seek to make maximum impact with our journalism which is entirely consistent with the BBC’s editorial guidelines and values."[23][24] Doughty said on Twitter that he had resigned "shortly before I did the interview so there was not time for spin doctors to start smearing me".[23]

Doughty lives in the Splott area of Cardiff. He has been a Cub and Scout leader since 2004, and is a Cardiff Cityseason ticket holder.[25] He features in the Pink List of leading Welsh LGBT figures.[26]